This invention relates to waterbeds, and in particular, a coupling for filling and draining waterbed mattresses.
Waterbed mattresses are provided with valves for filling and draining the mattress. The valve can be provided with an exteriorly male-threaded fill neck. To fill the mattress, a conduit such as a garden hose is connected to a water source. A coupling is required for interposition between the male-threaded fitting on the outer end of the garden hose and the exteriorly male-threaded fill neck of the waterbed.
A suitable coupling is described in U.S. Pat. No. 4,212,335. That coupling includes a tube for telescopic insertion into the male-threaded fill neck and a female-threaded fitting on the outer end of the tube for coupling with the male-threaded fitting of the garden hose.
A problem with this prior art coupling is that when draining the waterbed mattress, the end of the tube inserted into the mattress can become plugged by the vinyl walls of the mattress being sucked into the open end of the tube as the water levels drops. Thus, with such a coupling, it is possible to only partially drain a waterbed mattress using a siphon.
Another problem with the prior art coupling is that the female-threaded fitting on the outer end of the tube is fixed relative to the tube. To connect the fitting onto a garden hose often requires screwing the garden hose into the fitting, which is difficult and can kink the garden hose.
In view of these problems, it is apparent that there is a need for a waterbed filling unit which is easy to use, is practical, reliable, durable, and which can be used for substantially completely draining waterbed mattresses.